1. Field of the Invention
The present invention relates to a socket for an electrical part for detachably holding an electrical part such as semiconductor (called xe2x80x9cIC packagexe2x80x9d herein) having, particularly, an improved structure of a guide structure for guiding the electrical part at a time of accommodation thereof into a socket.
2. Prior Art of the Invention
In the known art, there has been provided an IC socket as a xe2x80x9csocket for an electrical partxe2x80x9d for detachably holding an IC package as an xe2x80x9celectrical partxe2x80x9d.
FIGS. 10A and 10B, for example, show a portion of such IC socket 1, which comprises a socket body 2 of so-called a two-body structure having a base 3 and a slide plate 4 disposed on the upper side of the base 3 to be slidable thereon. A number of contact pins 5 are disposed to the base 3 of the socket body 2.
Each of the contact pin 5 are formed, at its upper portion, with an elastically deformable movable contact portion 5a and a stationary contact portion 5b. When the slide plate 4 is slid, in the left side direction in the figures, the movable contact portion 5a is elastically deformed to thereby widen the distance between both the contact portions 5a and 5b as shown in FIG. 10A and, on the other hand, when the slide plate 4 is slid in the right side direction, the distance between these contact portions 5a and 5b is made narrow as shown in FIG. 10B.
Furthermore, the slide plate 4 has a structure capable of accommodating an IC package 6, and guide portions 4a for guiding the IC package 6 to a predetermined position are disposed to both end edge portions of the slide plate 4 so as to project upward.
According to such structure, when the IC package 6 is mounted to the predetermined position, the slide plate 4 is slid in the left side direction as shown in FIG. 10A so as to open the distance between both the contact portions 5a and 5b of the contact pin 5. Under the state, the IC package 6 is guided by the guide portions 4a at both end edge portions of the slide plate 4 to thereby mount the IC package 6 to the predetermined position on the slide plate 4. During this operation, a terminal 6a having a pin-shape of the IC package 6 is inserted between both the contact portions 5a and 5b. A number of such terminals are disposed so as to correspond to the contact pins 5, respectively.
Thereafter, when the slide plate 4 is moved in the right side direction as viewed in FIG. 10B, the movable contact portion 5a is returned by an elastic force thereof so as to clamp the terminal 6a between both the contact portions 5a and 5b and hence establish an electrical connection therebetween.
FIGS. 11 and 12 show other conventional examples of the IC socket 1, in which a top plate 8, as a stationary portion, is disposed on the base 3 through the slide plate 4.
When the slide plate 4 is slid in the left side direction as viewed in FIG. 11, the movable contact portion 5a of the contact pin 5 is elastically deformed so as to open the distance between both the contact portions 5a and 5b. Under the state, an IC package 9 is guided by guide portions 8a disposed at both end edge portions of the top plate 8 to thereby mount the IC package 9 to the predetermined position on the top plate 8. During this operation, a solder ball 9a as a terminal of the IC package 9 is inserted between both the contact portions 5a and 5b. 
Thereafter, when the slide plate 4 is moved in the right side direction, the movable contact portion 5a is returned by an elastic force thereof so as to push the solder ball 9a of the IC package 9 to thereby slide the IC package 9 in the right direction (FIG. 12), and hence to clamp the solder ball 9a between both the contact portions 5a and 5b, thus establishing an electrical connection therebetween.
However, with the conventional structure shown in FIGS. 10A and 10B, the guide portions 4a for guiding both the end edge portions of the IC package 6 is formed to both end portions in the moving direction of the slide plate 4. Then, according to this structure, when the distance L1 between these guide portions 4a is set to be slightly wider than the width L2 of the IC package 6, there is a fear of giving an adverse affect on the contacting state between the contact portions 5a and 5b and the pin-shaped terminal 6a. That is, by setting the distance L1 between these guide portions 4a to be slightly wider than the width L2 of the IC package 6, the IC package 6 can be mounted to the predetermined position of the slide plate 4. However, under such setting, when the slide plate 4 is moved from the state shown in FIG. 10A to the state shown in FIG. 10B, the pin-shaped terminal 6a of the IC package 6 abuts against the stationary contact portion 5b of the contact pin 5, and thereby, rightward movement of the IC package 6 is limited and the guide portions 4a of the slide plate 4 interfere with the left side end edge portion 6b of the IC package 6. Thus, the movement of the slide plate 4 is limited, the returning amount of the movable contact portion 5a is made small, and hence, the movable contact portion 5a is not sufficiently contacted to the pin-shaped terminal 6a, thus providing a problem (see FIG. 10B).
Further, with the conventional structure of FIGS. 11 and 12, the guide portions 8a for guiding both the end edge portions of the IC package 9 are formed to both the end portions of the top plate 8. Then, according to such structure, when the distance L1 between both the guide portions 8a is set to be slightly wider than a width L2 of the IC package 9, there is a fear of giving an adverse affect on the contacting state between the contact portions 5a and 5b and the solder ball 9a of the IC package 9. That is, by moving the slide plate 4 rightward, the solder ball 9a of the IC package 9 is pressed during the returning motion of the movable contact portion 5a to thereby slide the IC package in the right direction as viewed in figures. Therefore, the right end edge portion 9b of the IC package 9 interferes with the guide portions 8a, thus limiting the movement thereof and, hence, there is a fear of providing an insufficient contact state between the stationary contact portion 5b and the solder ball 9a. 
An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art mentioned above and to provide a socket for electrical parts capable of ensuring a good guiding performance of the electrical part at the accommodation time thereof as well as achieving a good contact condition of a contact pin to a terminal of the electrical part.
This and other objects can be achieved according to the present invention by providing, in one aspect, a socket for an electrical part which comprises a socket body having a stationary portion to which a number of contact pins are disposed so as to be contacted to or separated from a number of terminals, respectively, disposed to an electrical part, each of the contact pins having first and second contact portions between which each of the terminals is clamped, the socket body being provided with a slide plate to be transversely slidable in a usable state of the socket, and in which one of said first and second contact portions is displaced by sliding the slide plate to thereby open or close the first and second contact portions,
wherein the stationary portion is formed with a first guide portion for guiding a front side end edge portion, of the electrical part, in a sliding direction of the slide plate at a time of opening the contact portions of the contact pin and the slide plate is formed with a second guide portion for guiding the front side end edge portion, of the electrical part, in the sliding direction of the slide plate at a time of closing the contact portions of the contact pin.
In a preferred embodiment, the slide plate is mounted to an upper portion of the stationary portion of the socket body to be movable and the electrical part is mounted on the slide plate. The stationary portion of the socket body comprises a base member on which the contact pins are arranged, and the first guide portion is provided for the base member and said second guide portion is provided for the slide plate.
Further, it may be possible that the stationary portion of the socket body comprises a base member on which the contact pins are arranged and a top plate on which the electrical part is mounted, the slide plate being disposed between the base portion and the slide plate and the first guide portion being provided for the top plate and the second guide portion being provided for the slide plate.
In a more detailed aspect, there is provided a socket for an electrical part comprising:
a socket body having a stationary portion;
a number of contact pins disposed to the stationary portion so as to be contacted to or separated from a number of terminals, respectively, disposed to an electrical part, each of the contact pins having first and second contact portions between which each of the terminals is clamped;
a slide plate provided for the socket body to be transversely slidable in a usable state of the socket;
an operation member provided for the socket body and adapted to transversely move the slide plate when the operation member is moved vertically; and
a guide structure including a first guide portion formed to the stationary portion for guiding a front side end edge portion, of the electrical part, in a sliding direction of the slide plate at a time of opening the contact portions of the contact pin and including a second guide portion formed to the slide plate for guiding the front side end edge portion, of the electrical part, in the sliding direction of the slide plate at a time of closing the contact portions of the contact pin.
According to the subject matters of the present invention mentioned above, the socket for an electrical part is formed with guide portions including a first guide portion formed to the stationary portion for guiding a front side end edge portion, of the electrical part, in a sliding direction of the slide plate at a time of opening the contact portions of the contact pin and including a second guide portion formed to the slide plate for guiding the front side end edge portion, of the electrical part, in the sliding direction of the slide plate at a time of closing the contact portions of the contact pin. Accordingly, the electrical part such as IC package can be surely guided to be mounted by means of the guide structure and the interference between the guide portions and the electrical part can be effectively prevented, thus realizing a stable contacting state between the terminal of the electrical part and the contact pin.
The nature and further characteristic features of the present invention will be made more clear from the following descriptions made with reference to the accompanying drawings.